The Target_init entity a.k.a. How to remove weapons

"Init" defines a beginning of something. And that's why it removes everything from the player so he has nothing than the stuff from the spawn.
For using this entity you just have to create a trigger_multiple and connect it to the target. All you can do in the entity window is to set the spawnflags:

spawnflags: They are all self-explanatory. If you tick keeparmor then you won't loose your armor when you go through the trigger, but the rest,
like weapons, powerups etc. You can also use keeparmor, keephealth and keepweapons. Only your powerups and holdables will be withdrawn. Just try out all the combinations which this entity envolves.

If you want to remove the machinegun, too, then you have to use "32" as "spawnflags" value. But if you do this, keep in mind that really everything will be removed from the player.
The "Removemachinegun" value written in the description window isn't exisiting anymore. The best way to remove the machinegun is to create a trigger box around the player_deathmatch or player_start so he has to abstain from it the whole run.